Hemodynamics induced after acute reduction of proximal thoracic aorta compliance.

OBJECTIVE

to investigate the affect of reduced aortic compliance on cardiovascular hemodynamics.

MATERIALS AND METHOD

fourteen Yucatan miniature swine were divided into two equal groups, a Sham Operated Group and a Banding Group. A Teflon prosthesis was wrapped around the aortic arc in order to limit proximal aortic compliance (Banding Group). Data were recorded operatively (after implantation of a pressure sensor and a flow probe in the ascending aorta), after banding (only in the Banding Group) and at 2 days postoperatively.

RESULTS

after banding, compliance decreased by 52 +/- 13% ((-)X +/- SEM) (p < 0.01) while systolic and pulse pressure increased by 37 +/- 8% (p < 0.05) and 87 +/- 31% (p < 0.01), respectively. Diastolic pressure, mean blood pressure, cardiac output and systemic vascular resistance did not change significantly. Aortic characteristic impedance increased nearly 2.5 times. Amplitudes of forward and reflected pressure waves (derived from the aortic pressure wave) increased by 96 +/- 41% and 174 +/- 46%, respectively (p < 0.05), while the time delay between the two decreased by 36 +/- 7% (p < 0.05).

CONCLUSIONS

about half of the total arterial compliance is located in the proximal thoracic aorta. Arterial reconstruction of the proximal aorta with a non-compliant graft results in a significant decrease in systemic arterial compliance, which in turn increases systolic and pulse pressure. The development of more compliant prosthesis, which matches the host artery compliance, is expected to reduce the hemodynamic changes induced after their implantation.